沥青混合料探地雷达图像正演模拟与扩散研究

Research on forward simulation and diffusion of asphalt mixture ground penetrating radar image

针对探地雷达常因缺乏异常图像的客观评判标准和检测资料具有多解性与主观经验性,无法达到道路无损检测相关要求的问题,首先通过正演模拟为探地雷达理论研究提供了方向,然后基于时域有限差分算法和扩散方程理论,对沥青混合料的探地雷达图像进行正演模拟和电磁波在沥青混合料中的扩散进行了数值分析。结果表明:沥青混合料探地雷达图像正演模拟具有可行性;将gprMax建模结果与扩散方程的解析解拟合获得的扩散率D和损耗σ,可以用作表征混凝土结构完整性的新电磁指标。

In view of the problems that ground penetrating radar(GPR)cannot meet the requirements of road nondestructive testing because of the lack of objective evaluation criteria of abnormal images and the multi-solution and subjective experience of detection data,the forward simulation provides a direction for the theoretical research of GPR.Based on FDTD and one-dimensional diffusion equation,this paper mainly performs forward simulation of ground penetrating radar image of asphalt mixture and electromagnetic wave in asphalt mixture.Numerical analysis of diffusion is performed.The results show that the forward simulation of the asphalt mixture ground penetrating radar image is feasible;the"diffusion rate D"and"dissipationσ"obtained by fitting the gprMax modeling result to the one-dimensional analytical solution of the diffusion equation can be used as a new electromagnetic index to characterize the integrity of concrete structures.